Identification and molecular mapping of PmHNK54: a novel powdery mildew resistance gene in common wheat

Powdery mildew of wheat is caused by Blumeria graminis (DC.) Speer f. sp. tritici (Bgt). Wheat line Zheng 9754 is resistant in Henan Province. In seedling tests with seven Bgt isolates, Zheng 9754 had a different reaction pattern from those of lines Khapli with Pm4a, Armada with Pm4b, 81-7241 with Pm4c and Lankao 906 with PmLK906. F-1 hybrids, 516 F-2 plants and 327 F-2:3 lines derived from Zheng 9754/Chinese Spring (CS) were used for resistance gene tagging and linkage analysis. Simple sequence repeat (SSR) markers were used to test the two parents and resistant and susceptible bulks. Subsequently, three polymorphic markers were used for genotyping the F-2 and F-2:3 populations. Powdery mildew resistance in Zheng 9754 was conferred by a single dominant gene, tentatively designated PmHNK54, flanked by SSR markers Xgwm312, Xgwm372 and Xbarc5 on chromosome 2AL. The resistance gene was closely linked to Xbarc5 and Xgwm312, with genetic distances of 5.0 and 6.0 cM, respectively, and located on the chromosome bin 2AL-1-0.85 in the test with a set of deletion lines. The results suggested that PmHNK54 in Zheng 9754 is a new powdery mildew resistance gene in common wheat.